The present invention relates to DNAs encoding a major allergen of house dust mites, replication vectors, plasmids and host cells which have a concern in the DNAs, and the use thereof.
Allergic diseases generally have several kinds of symptoms which are developed by sensitization of antigen causing the diseases, in which IgE antibody (reagin antibody) specific for allergen in blood serum and tissue is produced, the antibody is exposed again to the antigen and the antibody reacts with the antigen in each tissue.
There is a desensitization therapy as a method for curing drastically the allergic diseases. In the method, the causative antigen is repeatedly administered to a patient in small doses, while the dose is gradually increased according to the symptoms. It is considered that, by the therapy, blocking antibody is produced, the production of the IgE antibody is controlled and the amount of histamine derived from a mast cell is lowered to give treatment effect.
On the other hand, it appears that allergic diseases such as bronchial asthma, childhood asthma, atopic dermatitis and the like are mainly caused by allergy to mites living in house dust. Several kinds of proteins of major mite allergens have been identified (Platts-Mills et al., J. Allergy Clin. Immunol., 80, 755 (1987)). The above desensitization therapy of the allergic diseases which uses the major allergens is very effective. However, it is impossible to prepare a large amount of purified allergens which are required in the therapy.